Endemic dimorphic fungi

Endemic dimorphic infections are acquired by inhalation of fungal spores which undergo a thermal transition to a yeast-like phase in the host. The causative organisms are geographically restricted and are isolated from the environment; likewise, the infections are associated with people living in, or visiting, these endemic regions. The clinical presentations range from asymptomatic to chronic, and disseminated, depending on the host immune status and other risk factors. The infections and their causative agents are: histoplasmosis (Histoplasma capsulatum), paracoccidioidomycosis (Paracoccidioides brasiliensis/lutzii), blastomycosis (Blastomyces dermatitidis/gilchristii), coccidioidomycosis (Coccidioides immitis/posadasii), talaromycosis (previously penicilliosis; Talaromyces [Penicillium] marneffei), and emmonsiosis (Emmonsia species). Diagnosis relies on microscopy and culture, histology, and immunological detection. Owing to their infectious nature, all of these organisms must be handled using biosafety level-3 containment. Treatment is based around azole administration, usually itraconazole, with amphotericin B for the more severe forms or for the most at risk patients.